The field of application of the present invention is the safety of vehicles with tires, and more particularly the estimation of the inflation and the detection of blow-outs in said tires.
Patent application US 2004/0133400 describes a system and a method for estimating the inflation state of one of the four tires of a vehicle. Said method and system are limited by the computing, straight-line and constant speed conditions, with only one tire sustaining a loss of pressure. Similarly, the document does not disclose detection of a slow loss of pressure.
Patent application US 2005/0171723 describes a system for estimating the inflation state of a tire using a spectral analysis of the vibration modes of the tire between 20 and 40 Hz. The peak frequency thus obtained differs in frequency depending on the inflation state of the tire. The limitation of said estimation system are a variable difficulty in obtaining the required vibration mode, variable difficulty depending on whether the tire is a driving tire or not, the state of the pavement or the side of the pavement used.
International patent application WO 2005/005173 discloses a method and a system for determining the difference in the diameter of said tire relative to the expected diameter, and the study of the vibration of said tire. From these two information items, the method and the system determine the pressure of said tire. The determination method and system are active only on straight road sections and demand signal processing that is costly and difficult to apply.
The systems and methods described in the foregoing documents have serious limitations associated with the conditions of use. Notably, stable running conditions are required such as movement in a straight line, and a stable speed, limiting the utility of such systems on journeys that are frequently made. Moreover, certain cited methods and systems require a comparison between the state of the monitored tire and the state of at least one of the other tires. The result of this is that a simultaneous loss of pressure of the monitored tire and of the tires used as reference leads to a detection malfunction.